# Michael Walter

Office: L237, QuSoft/CWI Phone: +31 (0)20 592 4328 E-Mail: m.walter@uva.nl

I am an Assistant Professor at the University of Amsterdam (KdVI, ITFA, ILLC) and a Senior Researcher at QuSoft. My office is located at the Centrum Wiskunde & Informatica (CWI).

My research is in quantum information theory and its connections to mathematics, fundamental physics & computing. I am in part supported by an NWO Veni grant on Quantum bits in space and time. I am part of the NWA quantum/nano route and a member of the Geometry and Quantum Theory mathematical research cluster.

Motivated by quantum information, I also study mathematical problems in representation theory and invariant theory through the lens of classical and quantum computation.

Curriculum vitae: [pdf]

# News

Together with Peter Bürgisser, I am organizing a minisymposium on “Efficient algorithms for geometric invariant theory” at the SIAM Conference on Applied Algebraic Geometry 2019.

~~I am currently looking to hire a ~~**postdoc in quantum information science**. For more information and to apply, see here.

Together with Maris Ozols, I organized a web class for high-school students to learn about quantum computing. See here for more details.

I recently visited the Science Café Nijmegen to discuss about space-time tangled up in quantum information. See here for some impressions.

Together with Ankit Garg, Rafael Oliveira, and Avi Wigderson, I organized a workshop on scaling algorithms and applications at FOCS 2018. See here for details.

New article published in PRX: popular summary & article

# Group

- Bas Dirkse (PhD candidate), multiparty protocols for quantum networks
- Yinan Li (postdoctoral researcher)
- Freek Witteveen (PhD candidate), quantum information & field theory
- Emma Loos (MSc project)
- Jeroen Dekker (MSc project)
- Philip Verduyn Lunel (MSc project)

**Alumni:**

- Raja Damanik (MSc project on optimality in stabilizer testing)
- Casper Guyrik (MSc project on quantum algorithms for factoring and post-quantum RSA, supervised by Ronald de Wolf)
- Philip Roeleveld (BSc project on a truncated tensor scaling algorithm)
- Wouter Borg (BSc project on entanglement in the stabilizer formalism)

Next group meeting: See Slack.

**If you are interested in doing a PhD in my group, please get in touch for further information (with a brief summary of research interests, CV, and email addresses of references).**

# Publications and Preprints

See the **arXiv** (and also **GitHub**).

# Teaching

In Spring 2019, Maris Ozols and I will offer a course on *Quantum Information Theory* in the MasterMath program.
See **here** for more information.
Guus Regts and I will also organize the *Master Seminar in Algebra, Geometry and Mathematical Physics*, see **here**.

See here for introductory lectures on quantum information, field theory, and gravity (with an emphasis on links between these fields).

In Spring 2018, I tought a course on *Symmetry and Quantum Information*.
See **here** for all course material.
I previously taught a similar course at Stanford University.
Watch this lecture as a teaser.
I also taught an abridged version of this course at IES in Cargese.

~~See here and here if you are looking for a Google Summer of Code project!~~

# Quantum Software and Society

- Nature Insight
- Quantum software manifesto
- Ronald de Wolf’s essay on the impact of quantum computing on society
- John Preskill’s essay on noisy intermediate-scale quantum technology
- Gate-level quantum software platforms overview as of July 2018

# Selected Talks

- “An invitation to tensor networks”, IAS 2018 [video]
- “Quantum Information and Holography”, DESY 2018 [pdf] [video]
- “Schur-Weyl Duality for the Clifford Group: Property testing, de Finetti representations, and a robust Hudson theorem”, QIP 2018, Boulder 2018, Bad Honnef 2018 [pdf] [video] [pdf] [pdf]
- “Quantum entanglement and space-time”, Groningen 2018 [html] [video]
- “Convexity, marginals, and moment polytopes”, IAS 2018 [pdf] [video]
- “Introduction to Quantum Programming”, QuSoft 2018
- “Quantum marginal problem, tensor scaling, and invariant theory”, NMC 2018 [pdf]
- “Rigorous entanglement renormalization from wavelets”, KITP 2017, Caltech 2017, AEI 2018, Amsterdam 2018, GGI 2018 [pdf] [video] [pdf] [pdf] [pdf]
- “When is a quantum state a stabilizer state?”, QuSoft 2017, QuTech 2018 [pdf]
- “Bulk reconstruction, error correction, and recovery maps”, KITP 2017 [video]
- “Tensor network models of holography”, DESY 2017
- “When is a state a stabilizer state? Testing stabilizer states with six copies”, CWI 2017
- “Tensors and Quantum Physics”, Auburn 2017 [video]
- “Multiparty entanglement, random codes, and quantum gravity”, Coogee 2017 [pdf], “Multipartite entanglement in toy models of holography”, Simons Center for Geometry & Physics 2016 [pdf] [video]
- “Entanglement in random tensor networks”, Georgia Tech 2016 [pdf]
- “Holographic duality from random tensor networks”, MIT 2015, KITP 2016, Cologne 2016, IQC 2016 [pdf] [pdf] [video] [other]
- “Moment polytopes & computational complexity”, Berkeley 2015 [pdf]
- “The Holographic Entropy Cone”, ETHZ, Caltech, CRM 2015; QIP 2016 [pdf short] [video] [pdf long]
- “Kronecker coefficients and complexity theory”, Dartmouth 2015, Rome 2016 [pdf]
- “Topologically ordered models in higher dimensions”, QGQIT 2015 [pdf]
- “Random Quantum Marginals”, IAS 2014 [video]
- “A Heisenberg Limit for Quantum Region Estimation”, ISIT 2014 [pdf]
- “The Quantum Marginal Problem”, DPG Spring Meeting 2014 [pdf]
- “Entanglement Polytopes”, QIP 2013; QSIT Lunch Seminar [pdf] [video] [science] [pdf] [explorer]
- “Quantum Entropies and Representation Theory”, IHES 2013 [pdf]
- “Computing Multiplicities of Lie Group Representations”, FOCS 2012 [pdf] [video]
- “Quantum State Tomography of 1000 Bosons”, SPS Meeting 2012 [pdf]
- “Quantum Marginals and Classical Moments”, IMS 2013 [pdf]
- “Eigenvalue Distributions of Reduced Density Matrices”, ICMP 2012 [pdf]

# Software

- Solve the quantum marginal problem and compute entanglement polytopes using our new tensor scaling algorithm.
- Use wavelets to approximate ground states of free fermion theories.
- Prove new holographic entropy inequalities using the contractor
- Just a moment! – an algorithm for computing moment cones for the quantum marginal problem
- Explore entanglement polytopes
- Compute Kronecker coefficients using barvikron (Python) or the new Kronecker Maple package
- Download the quantum sandbox for Octave/Matlab

# Other

- Amsterdam Math-Physics Colloquium
- Workshop on Quantum Marginals at the Isaac Newton Institute in Cambridge [photo]
- QCRYPT 2011 at ETH Zurich
- Career advice
- Quantum information conference calendar